§3- FLANT DISEASES AND INSECTS. 



Plant diseases were unusually prevalent and serious during 

 1890, and insects were about normal in numbers and destruc- 

 tiveness. Among fungi, attention was particularly drawn to 

 the apple scab, especially in New York, as it was supposed 

 to be responsible for much of the apple failure. Grape dis- 

 eases were also serious, and for the first time the mildew and 

 rot invaded the vineyards of western New York to an alarming 

 extent. A new grape disease has also occasioned much alarm in 

 California, and a new trouble has arisen in western New York. 

 The New York disease fortunately bids fair to submit to such 

 treatment as thorough under-drainage and careful culture, but 

 the disease invading the Pacific coast is yet wholly obscure. 

 The New York disease is known as rust or blight, and is indi- 

 cated by a browning or shrivelling of the leaves and the con- 

 sequent death or retardation of the fruit. The injury first 

 appears as small reddish or brown discolorations between the 

 veins. So far as known, the trouble is a physiological one, 

 apparently due to cold and insufficiently drained soil, and it 

 was probably brought on, or at least augmented, by the ex- 

 cessive rains of 1890.* 



But experimentation has kept pace with the difficulties, and 

 it has been proved beyond all doubt that many of our worst dis- 

 eases and insects can be kept in check profitably by the use of 

 sprays. Grape growers in all the best grape regions are 

 adopting the copper sprays, and many orchardists are treating 

 apples, pears and other fruits with good success. In most 

 parts of the country the growers are following closel}^ upon 

 the experimenters in the application of fungicides and insecti- 

 cides. So great has become the general intererest in the sub- 

 ject that growers in several states are asking for the enact- 

 ment of laws looking to the control of plant diseases and in- 

 sects. It is only a question of a short time until nearly every 

 state will add this important labor to its government machin- 



*See Journ. M^-cology, vi. 95. 



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